EXTERNAL ANATOMY. WING FEATHERS. 
93 
the air, flying steadily and surely to its distant retreat, 
or wending its way from the banks of the Nile to the 
pestilential swamps of Sicily.* Besides these peculiarities 
in die wing of the heron, there is another, which it 
possesses in common with the bee-eaters 
and some of the swallows ; for although 
the ends of the quills are very obtuse, 
as if cut off" obliquely, they are notched 
or sinuated in the middle of the tip 
{fg. 46.), a sure indication, in all birds 
where this einargination is found, of 
very perfect mode of flight, whatever 
that mode may be. Nor is this sort 
of wing stricdy confined to examples 
in the grallatorial order ; for we find it in the green 
chatterers of India (Calyptomina), in the cock of 
the rock (Itvpicolu), and in the genus Promuropn. In 
the first of these die secondary quills are remarkably 
broad and deeply notched, and the tertials of the latter 
are divided into those long filaments which form such 
an elegant ornament to the egrets, and to the sacred 
ibis. This form of wing is perhaps at its minimum in 
some of the African Cinnyrida, or sun-birds, where the 
secondaries are little shorter, but much broader, than the 
primaries ; but the tertials, instead of being lengthened, 
as in the Ardeadw, are of the same length as the quills 
which precede them. 
(85.) Lastly, we come to abortive wings, or such 
as are incapable of being used as instruments of flight. 
These are of two kinds ; the first belong to land birds 
of the ostrich family, die second to the swimming order, 
and chiefly to the penguins, grebes, and awks. The 
difficulty of examining with critical accuracy such large 
birds as the Struthiovida, which are generally placed 
in glazed cases in our museums, will oblige us to confine 
the short notice we sliaU here take of their wings to 
* The lakes of I.er>ntini are the resort of numberless migratory aquatic 
birds ; but the miasma proved the death of many of the best sportsmen in 
the Mediterranean army, between 1806 and 1814. 
